That's basically it, yeah. If people walked past they just didn't see anything of interest, didn't notice anything, didn't feel the need to look. Giving out a giant Keep Out vibe makes people interested, Hogwarts was just a feeling of nothing there so why bother going near.
That sounds good to me. Maybe something to help keep demons out? No offense to you, of course! The bad demons! We don't want them sneaking in and possessing the werewolves.